1. Digestive Disease Center, Department of Internal Medicine, Soon Chun Hyang University School of Medicine, Cheonan, Republic of Korea
2. Digestive Disease Center, Department of Internal Medicine, Soon Chun Hyang University School of Medicine, Bucheon, Republic of Korea
3. Department of Internal Medicine, Hallym University Sacred Heart Hospital, Anyang, Republic of Korea
4. Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
5. Digestive Disease Center, Department of Internal Medicine, Soon Chun Hyang University School of Medicine, Seoul, Republic of Korea